Method for conditioning tobacco



Dec. 16, 1958 A. ROWELL 2,864,381

METHOD FOR CONDITIONING TOBACCO Filed Feb. I, 1956 2 Sheets-Sheet 1 INVENTOR a WW/Yfi.

Dec. 16, 1958 A. ROWELL METHOD FOR CONDITIONING TOBACCO 2 Sheets-Sheet 2Filed Feb. 1, 1956 INVENTOR I a. Wowell 8/ imxw mra Unit; d StatesMETHOD FOR CONDITIONING TGBACCG Lorne A. Rowell, Lachine, Quebec.Canada. assi nor to Imperial Tobacco (Iompany of Canada Limited,Montreal, Quebec, Canada Application February 1, 1956, Serial No.562,887

2 Claims. (Cl. 131-140).

This invention relates to a method for conditioning tobacco andparticularly to the conditioning of tobacco in its compressed state asit is received at the processing plant.

The invention consists essentially in setting up the compressed tobaccoin an insulated compartment into which air, conditioned as totemperature and moisture content, is pumped, and withdrawing theconditioned air from the chamber through the compressed tobacco tioningtobacco which have had varying degrees of suc' cess. Some have beenharmful to the tobacco itself while others involve many steps in theprocess, are time consuming and add a heavy expense. Most of theseprocesses involve opening up the compressed tobacco to allow individualleaves to be conditioned in a suitable atmosphere. Others call for theplaying of a stream of gas on the outer surface of the compressed blockof tobacco and peeling off the surface leaves as they becomeconditioned, the process being continued until the whole of thecompressed bulk has been treated. Another form of conditioning has beento insert steam pipes into the compressed tobacco and force the steamunder pressure through the tobacco to the surrounding atmosphere' Inthis methodthe steam boiler provides the pressure necessary to forcemoisture vapor through the tobacco. in consequence, the temperatures ofthe vapor must be greater than 212 F. Temperatures this high areconsidered by most manufacturers too high and consequently harmful tothe. tobacco. Still another method of conditioning compressed tobaccoisby a vacuum process. The equipment required for this method is verycostly as also are the operating costs.

The object of the present inventionis therefore to condition thecompressed tobacco by the creation of a pressure differential throughthe tobacco which will allow conditioned air of any desired temperatureto pass through the tobacco and in the process give up its heat andmoisture to the tobacco evenly throughout its compressed bulk.

A further object of the invention is to supply controlled conditionedair to an insulated chamber enclosing the compressed tobacco and to passthat conditioned air through the tobacco for'recirculatio-n in a closedsystem.

- A further object of the invention is to provide means whereby the endsof the compressed tobacco is kept sealed to prevent short circuiting ofthe conditioned air r the and to constrain it to flow through thetobacco in layers of more orless equal radii to an axial evacuationprobe.

These and other objects will be apparent from the allowing specificationand the accompanying drawings in which Fig. 1 is a schematic verticalelevation of a typical tobacco conditioning apparatus.

Fig. 2 is a vertical section on the line 22 of Fig. 1. ig. 3 is avertical section showing an air evacuation outlet and means forattachment to a probe.

Pig. 4 is an enlarged partial vertical section showing the upper end ofa probe assembly and showingthe method of sealing the top of thecompressed tobacco to prevent short circuiting of conditioned air to theperforated pro-be.

Fig. 5 is an enlarged outside view ing the top apertures of the probewhich have been uncovered by the slumped tobacco.

Referring to the drawings, Figs. 1 and 2 show a typical assembly inwhich a chamber 1 is formed of insulated side walls 2 and top 3. Aninsulated door 4 can be mounted on hinges or be arranged to be liftedvertically in suitable guides. The chamber 1 is insulated to minimizecondensation and to conserve heat and, when in operation is keptcompletely closed except for the vent 5 on the top of the chamber whichallows the chamber to be kept at atmospheric pressure at all times.

The mass of compressed tobacco 6 as taken from bales or hogsheads areset on the wheeled dollies 7 for easy transportation into and out of thechamber 1, the dollies being of a size which will cover most of the-baseof the tobacco 6 to prevent air from entering the to bacco from below. Ahollow perforated probe 8 is pressed into the compressed tobacco 6 fromthe top as near the vertical axis of the mass as possible, the probepenetrating to the bottom of the mass as shown in Figs. 1 and 2. ."l'heprobe 8 has a flexible annular in chamber 1. The flexible cover 11covers completely the top of the cylindrical or rectangular pile ofcompressed tobacco and prevents air from short circuiting taro-ugh thetop of the tobacco into the upper perforations 13 of probe 8. r

The air conditioning and circulating system comprises a multi-stage fanto driven by the. motor 41. The inlet side 1? of the fan 16 is connectedto the suction pipe 18 which is divided into branch pipes 19 to connectwith as many probe coupling units as the chamber 1 is fitted with. Thesecoupling units consist of a flexible tube 29 secured at its upper endand within the chamber 1 to the lower end of the branch pipes 19, withthe pipe 19 and tube 24) being held securely to the top 3 of the chamberl by the clamp ring 21. The lower end of the tube 26 is secured to thefitting 22 by the ring23;

The fitting 22 is tapered at 24 to areduced diameter at 25 to take theflexible coupling sleeve 14 which is slipped over the top end of theprobe 8 after the dolly 7 carrying the compressed tobacco is rolledunder the coupling unit. Clamp rings 15 secure the flexible cousimilarto Fig. 4 but showing the top sealing cover following the tobaccodownwards as it slumps during conditioning and scal pling s eeve 14 tothe reduced diameter 25 of the fitting 22 and to the probe 8 by means ofthe screws 26.

A pipe 27 is connected to the discharge side of the fan 16 and isprojected horizontally into the chamber 1 to form the distributionheader 28 having branches 29 adapted to spray conditioned air into thetop of the chamber 1.

A high pressure steam pipe 36 is projected into the air discharge pipe27 and terminates in a nozzle 31 adapted to spray a jet of steam intothe air passing through the pipe 27 to the header 28. Steam requirements are determined by the temperature at the bulb 32 situated withinthe chamber 1. adjacent to the discharge branches 29 of the header 28 tocontrol the opening and closing of the valve 33 by the controller 34.The rate of temperature rise can be adjusted by the valve 35 on thesteam line 30 between the valve 33 and the nozzle 31.

A nozzle 36 within the air discharge pipe 27 ahead of the nozzle 31projects a spray of water from the water supply line 37, the spray ofwater being controlled by the valve 38. The water spray from the nozzle36 is atomized by high pressure steam fed from the steam line 30 throughthe pipe 39 and controlled by the valve 40. Excess condensate in thedistribution header 28 is drained off through the drain pipe 42 into thefloor drain 43.

In the operation of this invention, the hollow perforated probe 8, ofminimum diameter, is first pressed down into the mass of compressedtobacco, the probe being placed as near as possible to the verticalcenter of the mass. The compressed tobacco can be placed on the dolly 7before or after insertion of the probe 8, whichever is most convenient.The flexible cover 11 and sleeve 9 are then fitted over the probe 8, thesleeve 9 being held on the probe by the elastic band 10 while theflexible cover is spread over the top surface of the tobacco so thatonly the sides of the mass of tobacco are exposed.

The dolly 7 is now wheeled into the chamber 1 and aligned under thecoupling sleeve 14 and the coupling is fitted over the open end of theprobe 8 and secured thereon by tightening up the screw 26 in the lowerclamp ring 15, the flexible tube 20 adjusting itself to the height ofthe probe 8.

The chamber 1 can be made to take any convenient number of compressedtobacco units, the capacity of the chamber being limited only by theproduction level required and the size of the conditioning installationavailable.

When the chamber has been loaded and the installation set in operation,the chamber 1 is filled with air delivered by the fan 16 through thepipe 27 and header 28, the air being conditioned by means of steam andwater introduced into the air from the nozzles 31 and 36. Normally thequantity of water introduced into the air is sufficient to maintain afog in the chamber 1, denoting slight supersaturation of the air.

The conditioned air, in passing from the chamber 1 and through thetobacco to the probe 8, gives up heat and moisture to the tobacco evenlythroughout the whole volume of the tobacco mass, the air being drawn outof the probe 8 through the pipe 19 to the intake side of the fan 16. Theperforations 13 are distributed over the length of the probe 8 so thatthe air fiow through the mass of the tobacco is substantially uniformfrom the top to the bottom of the mass.

The circulation of air through the system is maintained because of thepressure difference across the compressed tobacco, created by themulti-stage fan 16 and is re-circulated in re-conditioned form for aslong as is necessary to thoroughly condition the tobacco.

With the tendency of the tobacco to slump during the conditioningoperation, any tendency for the air to short circuit the tobacco andpass directly through the top perforations 13 of the probe, is preventedby the fiexiblc cover 11 which follows the slumping tobacco to keep thetop surface covered and sealed, so that the air must always pass throughthe tobacco from the sides in horizontal layers in line with theperforations '13 in the probe.

It should be noted that in this invention the circulating air in thesystem is a vehicle for the conveyance of heat and moisture to thetobacco. The only energy which can be lost is the slight amount throughradiation from the machine, condensation in the machine, and a smallamount of leakage at the vent 5. Most of the energy elivered to the fan16 by the motor 41 is transferred to the circulating air in the form ofheat which in turn is absorbed by the tobacco. These facts explain theextremely high thermal efficiency of this machine compared to most othertobacco conditioning machines. Moisture gains of as much as 36 lbs. havebeen obtained with the use of only 25 lbs of steam. The remaining gainof 11 lbs. being atomized water converted to vapour when mixed with thedry heat from the fan.

What I claim is:

1. The method of conditioning a compressed ma s of tobacco comprising,passing a hollow perforated probe vertically downwards through thecentral portion of the mass of tobacco, placing the mass of tobacco in achamher which is insulated to minimize condensation and to conserve heatand which is closed except for a vent which ensures that the chamberwill be maintained at atmospheric pressure during the tobaccoconditioning procedure, applying to the top and bottom surfaces of themass of tobacco cover. members which are substantially impermeable toair, connecting the upper end of the probe to a source of suction andcontinually introducing into said chamber during the conditioningoperation air which has been suitably conditioned as to heat andmoisture content. said process being characterized in that the sealingcover applied to the top of the mass of tobacco prevents air from shortcircuiting through the top of the mass of tobacco into the upperperforations of the probe as the tobacco slumps downwardly along theprobe'during the conditioning thereof.

2. The method of conditioning a compressed mass of tobacco comprising,passing a hollow perforated probe vertically downwards through thecentral portion of the mass of tobacco, placing the mass of tobacco inclosed chamber which is insulated to minimize condensation and to'conserveheat, applyingto the top and bottom surfaces of the mass oftobacco cover members which are substantially impermeable to air,connecting the upper end of the probe to a source of suction andcontinually introducing into said chamber during the conditioningoperation air which has been suitably conditioned as to heat andmoisture content, said process being characterized in that the sealingcover applied to the top of the mass of tobacco prevents air from shortcircuiting through the top of the mass of tobacco into the upperperforations of the probe as the tobacco slumps downwardly along theprobe during the conditioning thereof.

References Cited in the file of this patent UNITED STATES PATENTS123,011 Goodwin Jan. 23, 1872 257,724 Kruckemeyer May 9, 1882 1,958,863Rapeanu May 15, 1934 2,016,535 Bogaty Oct. 8, 1935 2,121,370 Touton June21, 1938 FOREIGN PATENTS 546,402 Germany Mar. 15, 1932

